app.js

//Headers are meta data in request
const express=require('express');
const bodyParser=require('body-parser');
const multer=require('multer');
const errorController=require('./controllers/error');
const adminData=require('./routes/admin');
const shopRoutes =require('./routes/shop');
const authRoutes=require('./routes/auth');
//const expressHbs=require('express-handlebars');
const path=require('path');
const User=require('./models/user');
const mongoose=require('mongoose');
const session=require('express-session');
const csrf=require('csurf');
const flash=require('connect-flash');
const MongoDBStore=require('connect-mongodb-session')(session);

const MONGODB_URI='MONGODB_URI';

const app=express();
const store=new MongoDBStore({
  uri:MONGODB_URI,
  collection:'sessions'
});
const csrfProtection=csrf();

const fileStorage=multer.diskStorage({
  destination:(req,file,cb)=>{
    cb(null,'images');
  },
  filename:(req,file,cb)=>{
    cb(null,file.originalname);
  }
});

const fileFilter=(req,file,cb)=>{
  if(file.mimetype==='images/png'||file.mimetype==='image/jpg'||file.mimetype==='image/jpeg'){
    cb(null,true);
  }
  cb(null,false);
};

app.set('view engine','ejs');
app.set('views','views');

app.use(bodyParser.urlencoded({extended:false}));
app.use(multer({storage:fileStorage,fileFilter:fileFilter}).single('image'));
app.use(express.static(path.join(__dirname,'public')));
app.use('/images',express.static(path.join(__dirname,'images')));

app.use(session({secret:'my secret',resave:false,saveUninitialized:false,store:store}));

app.use(csrfProtection);
app.use(flash());

app.use((req,res,next)=>{
  if(!req.session.user){
    return next();
  }
  User.findById(req.session.user._id)
  .then(user=>{
    if(!user){
      return next();
    }
    req.user=user;
    next();
  })
  .catch(err=>{
    throw new Error(err);
  });
});

app.use((req,res,next)=>{
  res.locals.isAuthenticated=req.session.isLoggedIn;
  res.locals.csrfToken=req.csrfToken();
  next();
});

app.use('/admin',adminData);
app.use(shopRoutes);
app.use(authRoutes);
app.use(errorController.get404);
mongoose
  .connect(
    MONGODB_URI
  )
  .then(result=>{
    app.listen(3000);
  })
  .catch(err=>{
    console.log(err);
  });